Ultrasound-Energy Consumption During Phases of Phacoemulsification of Nuclear Cataracts Using Femtosecond Laser: A Comparative Study

Figures & data

Figure 1 Pentacam nucleus staging (PNS).

Figure 2 Lens fragmentation used in all cases in the FLACS group: sextants with lens softening, grid spacing 350 µm, seg-soft spacing 200 µm.

Table 1 Age differences among cases in FLACS and CPS groups and their subgroups

		n	Age (mean ± SD), years	P-value
FLACS		117	62.5±8.1	0.96
CPS		133	62.4±8.4
Subgroup A	FLACS	35	60.2±11.6	0.99
	CPS	42	60.4±10.7
Subgroup B	FLACS	40	60.3±4.6	0.54
	CPS	47	64.4±6.6
Subgroup C	FLACS	42	62.8±6.8	0.77
	CPS	44	62.8±7.3

Abbreviations: FLACS, femtosecond laser–assisted cataract surgery; CPS, conventional phacoemulsification..

Table 2 Intraoperative parameters in FLACS and CPS groups

	FLACS (n=117)	CPS (n=133)	P-value
	Mean ± SD	Mean ± SD
EFX split	9.96±8.8	10.28±8.35	0.49
EFX quadrant	17.33±14.22	19.96±15.1	0.18
Average US (%)	5.9±3.3	5.8±3.4	0.45
Total US time (seconds)	72.0±45.8	66.5±45.0	0.44

Abbreviations: FLACS, femtosecond laser–assisted cataract surgery; CPS, conventional phacoemulsification; US, ultrasound.

Table 3 Intraoperative parameters in FLACS and CPS subgroups

	Subgroup A (NC 1–2)			Subgroup B (NC 3–4)			Subgroup C (NC 5–6)
	FLACS (n=35), mean± SD	CPS (n=42), mean ± SD	P-value	FLACS (n=40), mean ± SD	CPS (n=47), mean ± SD	P-value	FLACS (n=42), mean ± SD	CPS (n=44), mean ± SD	P-value
EFX split	0.26±0.44	0.45±0.5	0.08	7.82±2.31	10.34±2.83	0.0001	20.07±4.93	19.59±4.7	0.86
EFX quadrant	2.11±1.64	2.29±1.04	0.49	14.3±5.92	20±4.65	<0.0001	32.9±0.45	36.8±8.98	0.05

Abbreviations: FLACS, femtosecond laser–assisted cataract surgery; CPS, conventional phacoemulsification; NC, nuclear cataract; US, ultrasound; EFX split, US energy required for nucleus splitting; EFX quadrant, US energy required for quadrant removal.

Figure 3 Anterior-segment axial scan by spectral-domain OCT of Catalys precision-laser system. Dense cataracts were noticed to extend posteriorly beyond the minimum laser-fragmentation offset of 500 μm from the posterior capsule.

Figure 4 Dense (brunescent) cataract subgroup C. Nucleus-cracking phase. Similar US-energy levels were utilized in FLACS (A) and CPS (B). During quadrant removal, less US energy was utilized in the FLACS (C) than the CPS (D) subgroups.